Physics
Chapter 4 Review
Name:__________________
Date:_________ Period:____
1. Newton’s First Law states that an object _____.
a. at rest will remain at rest unless acted on by an outside force.
b. Will continue moving at the same velocity unless acted on by an outside force.
c. Will continue moving in a straight line unless acted on by an outside force.
d. That is not moving will never move unless a force acts on it.
e. All of the above
2. The law of inertia applies to _____.
a. moving objects
b. objects at rest
c. both moving and nonmoving objects
3. After a cannon ball is fired into frictionless space, the amount of forced needed to keep it going equals _____.
a. twice the force with which it was fired
b. the same amount of force with which it was fired
c. on half the force with which it was fired
d. one quarter the force with which it was fired
e. zero, since no force is necessary to keep it moving
4. A sheet of paper can be withdrawn from under a container of milk without toppling it if the paper is jerked away
quickly. The reason this can be done is that _____.
a. the milk carton has very little weight
b. there is an action-reaction pair operating
c. gravity pulls very hard on the milk carton
d. the milk carton has inertia
e. none of the above
5. One object has twice as much mass as another object. The first object also has twice as much _____.
a. inertia
b. velocity
c. gravitational acceleration
d. energy
e. all of the
above
6. Compared to its weight on earth, a 50 kg object on the moon will weigh _____.
a. less
b. more
c. the same amount
7. The mass of a dog that weighs 100 N is about _____.
a. 1 kg
b. 10 kg
c. 100 kg
d. 1000 kg
e. none of the above
8. The force required to maintain an object at a constant speed in free space is equal to _____.
a. zero
b. the mass of the object
c. the weight of the object
d. the force required to stop it
e. none of the above
9. An object following a straight line path at constant speed _____.
a. has a net force acting on it in the direction of motion
b. has zero acceleration
c. must be moving in a vacuum
d. has no forces acting on it
e. none of the above
10. Friction _____.
a. acts in a direction that opposes the motion of an object
b. comes from microscopic bumps that act as obstructions to the objects motion
c. is the name given to the force acting between surfaces sliding past one another
d. all of the above
e. none of the above
11. A 10 N force and a 30 N force act on an object in opposite directions. What is the magnitude of the net force
acting on the object?
a. 40 N
b. 30 N
c. 20 N
d. 10 N
e. none of the above
12. You would have the largest mass of gold if your chunk of gold weighed 1 N on _____.
a. the moon
b. Earth
c. it doesn’t matter which planet you are on.
13. Equilibrium occurs when _____.
a.
b.
c.
d.
e.
all the forces acting on an object are balanced
the sum of the forces acting rightward equal the sum of the forces acting leftward.
the sum of the forces acting upward equal the sum of the forces acting downward.
the net force is zero.
all of the above.
14. What is the maximum resultant possible when adding a 3 N force and an 8 N force?
a. 24 N b. 11 N c. 8 N d. 5 N e. 3 N
15. What is the minimum resultant possible when adding a 3 N force and an 8 N force?
a. 24 N b. 11 N c. 8 N d. 5 N e. 3 N
16. Which has more mass, a kilogram of feathers or a kilogram of iron?
a. the feathers b. the iron
c. neither
17. Accelerations are produced by _____.
a. velocities
b. accelerations c. forces
d. masses
18. How does the acceleration of an object change in relation to its mass?
a. directly proportional
b. inversely proportional
c. acceleration doesn’t depend on mass at all
e. none of the above
It is _____.
19. The acceleration produced by a net force on an object is _____.
a. directly proportional the magnitude of the net force.
b. in the same direction as the net force
c. inversely proportional to the mass of the object
d. all of the above
e. none of the above
20. A heavy person and a light person parachute together and wear the same size parachutes. Assuming they open
their parachutes at the same time, which person reaches the ground first?
a. the light person
b. the heavy person
c. neither
21. A 10 kg brick and a 1 kg book are dropped in a vacuum. The force of gravity on the 10 kg brick is _____.
a. the same as the force on the 1 kg book
b. 10 times as much as the force on the 1 kg book
c. zero
22. An apple weighs 1 N. The net force on the apple when it is in free fall is _____.
a. 0 N
b. 0.1 N
c. 1 N
d. 9.8 N
e. none of the above
23. An apple weighs 1 N. When held at rest on top of your head, the net force on the apple is _____.
a. 0 N
b. 0.1 N
c. 1 N
d. 9.8 N
e. none of the above
24. A girl pulls a 10 kg wagon with a constant force of 30 N. What is the wagon’s acceleration?
a. 0.3 m/s2
b. 3.0 m/s2
c. 10 m/s2
d. 30 m/s2
e. 300 m/s2
25. An object has a constant mass. A constant force on the object produces constant _____.
a. velocity
b. acceleration c. both A and B d. none of the above
26. A force of 1 N accelerates a mass of 1 kg at the rate of 1 m/s2. The acceleration of a mass of 2 kg acted upon by
a force of 2 N is _____.
a. half as much
b. twice as much
c. the same
d. none of the above
27. A rock is thrown vertically into the air. At the top of its trajectory, the net force on it is _____.
a. less than its weight
b. more than its weight
c. equal to its weight
28. A block is dragged without acceleration in a straight line path across a level surface by a force of 6 N. What is
the frictional force between the block and the surface?
a. less than 6 N
b. more than 6 N
c. 6 N d. need more information to answer
29. A tennis ball and a solid steel ball the same size are dropped at the same time. Which ball has the greater force
acting on it?
a. the tennis ball
b. the steel ball c. neither
30. A student hits a nail with a hammer. During the collision, there is a force _____.
a. on the hammer but not the nail
b. on the nail but not the hammer
c. on the nail and the hammer
31. Forces always occur _____.
a. by themselves
b. as single quantities
c. in pairs
d. in triplets
32. An archer shoots an arrow. Consider the action force to be the bow string against the arrow. The reaction to this
force is the ____.
a. weight of the arrow.
b. air resistance against the bow.
c. friction of the ground against the archer’s feet.
d. grip of the archer’s hand on the bow.
e. arrow’s push against the bowstring.
33. An unfortunate bug splatters against the windshield of a moving car. Compared to the acceleration of the car,
the acceleration of the bug is _____.
a. larger
b. smaller
c. the same
34. An unfortunate bug splatters against the windshield of a moving car. Compared to the force of the car on the
bug, the force of the bug on the car is _____.
a. larger
b. smaller
c. the same
35. Another unfortunate bug splatters against the windshield of a moving car.
in velocity?
a. the car
b. the bug
c. both the same
Which undergoes the greater change
36. A person weighs 500 N. What is the mass of the person?
Fg = mg m = Fg/g m = 500 / 9.81 m = 51 kg
37. What is the resultant of a 5.0 N force acting vertically upward and a 3 N force acting horizontally?
C2 = a2 + B2 C = √(52 + 32) = 5.8 N @ 59o
38. A 200 kg bear grasping a vertical tree slides down at a constant velocity. What is the friction force between the
tree and the bear?
Ff
Fy = Ff – Fg = ma, where a = 0
Ff = Fg = 1962 N
Fg = 200kg * 9.81
39. A certain unbalanced force gives a 5 kg object an acceleration of 2.0 m/s2. What acceleration would the same
force give a 30 kg object?
F = ma = 5kg * 20 m/s2 so, F = 10 N
If F = 10 N and it is applied to a 30 kg object then
10N = 30 kg * a so, a = 10/30 or 0.3 m/s2
40. A net force of 1.0 N acts on a 2.0 kg object, initially at rest, for 2.0 seconds. What is the distance the object
moves during that amount of time?
Find acceleration F = ma a = F/m a = 1.0 N / 2.0 kg = 0.50 m/s2
x = vit + ½ at2 x = 0 + 1/2 (0.500 m/s2)(2.0s)2 = 1.0 m
41. Suppose you exert 400 N horizontally on a 50 kg crate on a factory floor, when friction between the crate and the
floor is 200 N. What is the acceleration of the crate? What is the coefficient of friction between the crate and the
floor?
(400N - 200N) / 50 kg = a = 4 m/s2
Ff = 200 N Ff = Fn  = Ff / Fn → 200 N / (50kg * 9.81) = 0.41
42. A 50 kg block of cement is sitting on the edge of a cliff. A 150 kg block hangs over a pulley on the edge. If the
coefficient of friction is 0.38 between the cement block and the cliff, what is the acceleration of the block?
- 6.4 m/s2
43. Bronco the skydiver whose mass is 50 kg, experiences 200 N of air resistance. What is the acceleration of his
fall?
Fr = 200 N
Fy = 200 N – 50 kg * 9.81 = 50 kg * a → a = -5.8
Fg = 50kg * 9.81
44. A 40.0 kg block is pushed along the floor with a constant applies force of 85.0 N that acts at an angle of 55˚ with
the horizontal. The block accelerates to the right at 6.00 m/s2. Determine the coefficient of friction between the block
and floor.
Fn
Fy = Fn + 85sin 55 – Fg = 0 → Fn = 40.0 kg *9.81 -85 sin 55 = 322.8 N
2
85.0 N Fx = 85 cos 55 – Ff = ma → 48.8 N – Fn = 40.0 kg * 6.00 m/s
solving for  we get  = (240 N – 48.8 N) / 322.8 = 0.6
Ff
Fg
45. A person with a blackbelt in karate has a fist that has a mass of 0.70 kg. Starting from rest, this fist attains a
velocity of 8.0 m/s in 0.15 s. What is the magnitude of the net force applied to the fist to achieve this level of
performance?
Solve for a, a = v/t 8.0 / 0.15 = 53.3 m/s2
F = ma F = 0.7 kg * 53.3 m/s2 = 37.3 N